Contact plate for use in a rectifying or contacting column



Aug. 21, 1956 w. KITTEL 2,759,720

CONTACT PLATE FOR uss IN A RECTIFYING OR CONTACTING COLUMN Filed March 5, 1952 2. Sheets-Sheet 1 ZINVENTOR WHLTER KITTEL Aug. 21, 1956 w. KITTEL 2,759,720

CONTACT PLATE FOR USE IN A'RECTIFYING OR CONTACTING COLUMN Filed. March 5. 1952 2 Sheets-Sheet 2 INVENTOR WQ LTER K ITTEL KTTORNEY United States Patent CONTACT PLATE FOR USE IN A RECTIFYING 0R CONTACTING COLUMN Walter Kittel, Gmunden, Austria Application March 5, 1952, Serial No. 274,994

Claims priority, application Austria March 10, 1951 7 Claims. (Cl. 261-114) This invention relates to rectifying or contacting col umns, wherein a liquid and a gaseous medium are brought into intimate contact, and more particularly to the construction of a contact plate for use in this type of contacting columns.

A contact plate arranged in a rectifying or contacting column has the task of causing an intimate contact of highest degree of the ascending gases or vapors with the descending liquid introduced into the column. This operation of the contact plate shall be carried out with an efficiency and an intensity, as high as possible, but in most cases it is also required that the contact plate offers a minimum of resistance to the flow of the ascending gases and vapors, has a maximum of working reliability and has a load range as wide as possible.

In a search for a satisfactory solution of these problems, contact plates for contacting columns have been developed in recent years which show quite some advantages. For example, a considerable simplification of the contact plates, with respect to their operation and construction, has been obtained by the exploitation of a certain portion of the kinetic energy, inherent in the gases or vapors, in the sense of creating a stationary or stable state of motion of the layer of liquid resting on the contact plate and being dammed thereon respectively by the gases or vapors themselves. This portion of the kinetic energy is that which, during the passage of the gases or vapors through said layer of liquid, is necessarily transmitted to the latter and substantially corresponds to the decrease of pressure of the gas or vapor occurring during this operation.

It has been found out that most of the requirements listed above, but not all of them, can be fulfilled by the construction of the hitherto customary contact plates of this type. Owing to the fact that such a customary contact plate operates according to a purely dynamic principle by making use of the kinetic energy of the gases not only for creating the state of motion of the layer of liquid but also for damming the latter, there is necessarily a lower load limit of the contact plate and, if the load is below said lower load limit, an extremely high reduction of the efficiency of the contact plate takes place, inasmuch as it has been found that the passage of the gases or vapors through a cohesive layer of liquid is the basic condition for a satisfactory effect of exchange. On the other hand, however-especially in View of the resistance to flow of the contact plate under higher loads it is not always possible to exclude this contingency by choosing a column of suificiently small diameter, so that above mentioned fact sometimes becomes a distinct disadvantage.

The present invention relates to a contact plate which overcomes the above mentioned disadvantage by the fact that the kinetic energy of the gases or vapors is utilized exclusively for the creation of a stationary or stable state of motion of the liquid during the passage of these gases or vapors through the contact plate without, at the same time, attempting to form the layer of liquid itself. In a contact plate according to the invention, the layer of liquid is formed or dammed, respectively, by a purely static mode of operation, i. e. by means of overflow pipes, in conjunction with gas inlet connecting branches or gas chimneys respectively, having their upper edges in a predetermined level above the surface of the contact plate as is customary in socalled bell contact plates or tunnel contact plates.

As in this way the dynamic eflects, which may be obtained according to the manner of dynamically eifec tive contact plates by the contact of the gases or vapors ascending in a column with the liquid descending therein, are restricted in this case to the creation of a stable state of flow in the sense of a stationary movement of rotation about the vertical axis of the contact plate in the layer of liquid resting on the contact plate. The gases or vapors are relieved from the additional task of causing themselves the damming of this layer of liquid, and a contact plate is obtained which displays an ideal behavior with respect to its load range and yet preserves fully the advantages found in purely dynamic contact plates for use in rectifying or contacting columns.

As said above, the passage of the gases or vapors through a cohesive layer of liquid is an important condition for a satisfactory effect of exchange. This condition is fulfilled in any case by a contact plate according to the invention, as the formation of the layer of liquid is entirely independent of the amounts of the gases or vapors ascending in the column. Thus, in a contact plate according to the invention the introduction of the gases or vapors into the layer of liquid in a uniformly determined tangential and radial direction assures the creation of the desired state of motion of the liquid, even if only very small amounts of gases or vapors are used.

On one hand, above mentioned feature of the contact plate according to the invention eliminates absolutely a non-uniform operation thereof which would cause a reduction of its efficienc such a non-uniform operation resulting from an oscillation or swaying of the layer of liquid may always be observed in the lower load ranges of the so-called bellor tunnel-contact plates, especially those with large opening ratios.

On the other hand, as it is just the opening ratio of a contact plate, in cooperation with the static height of the liquid above the gas outlets, by means of which the characteristic of resistance of the contact plate is determined, it will be readily understood from above, that, by a corresponding increase of the opening ratio of a contact plate according to the invention, the load range of the latter can be widened considerably also towards a higher value, inasmuch as in such a casein contrast to purely dynamic contact platesthis increase of the opening ratio is not coupled with a disadvantageous displacement of a lower load limit. If the tangential component of the gases or vapors entering the layer of liquid in a more or less horizontal direction is chosen in a proper relation to the radial component thereof by a corresponding arrangement of the direction of the individual gas outlet slots according to the manner known per se in dynamic contact plates, at the same time the additional effect is obtained, that an absolutely uniform flow pattern is maintained up to the highest loads, as the centrifugal force, increased by a higher rotation of the liquid, is compensated in the latter by the radial component of the kinetic energy of the gas directed towards the center of the contact plate.

Beside above explained wide load range of the contact plate according to the invention, exceeding to a great extent the load range of customary bellor tunnel-contact plates, the exchange system according to the invention has very important additional advantages.

Said additional advantages are caused mainly by the Patented Aug. 21, 1956.

fact that owing to the renewal of the surface, being coupled with the strong movement of the 'liquid on the contact plate and being much more intensive than that on customary bell-contact plates, the height of the liquid, essential for a high efiiciency of the contact plate may be held in this case at a considerably lower potential, inasmuch as the positive coupling between the movement of the liquid and the height of the dammed layer of the liquid, both being equally conditioned by the kinetic energy of the gases or vapors in purely dynamic contact plates, does not take place in a contact plate according to the invention.

Thus, on one hand, the resistance to flow of the contact plate, the degree of which being also influenced by the static height of the layer of liquid above the gas-outlets, as said before, is reduced further, i. e. it is reduced beyond the degree determined by the above mentioned increase of the opening ratio.

On the other hand, however, the liquid volume of the contact plate is reduced at the same time, so that the apparatus shows less inertia. In view of the large number of column-contact plates, sometimes of extremely large diameter, required for modern fine-fractionating plants, this feature is of great importance, especially for this type of plants, inasmuch as the maintenance of the desired high degree of sectional accuracy between the individual fractions is considerably better assured.

Of course, the method of operation of the contact plate according to the invention has also the additional advantages, known already in the dynamically acting contact plates with a rotating layer of liquid, such as: insensitiveness to the deposit of solids carried along in the liquid, insensitiveness to a slightly inclined position of the contact plate, an intensive separation of the liquid from the gases or vapors ascending from the contact plate in a strong vortex motion, etc.

Above characterized method of operation may be carried out in practice in many different ways, as long as the apparatus used imparts a motion of rotation to a statically conditioned layer of liquid on a column-contact plate about the vertical axis of the later by a correspondingly uniformly directed or aligned introduction of the gases or vapors to be brought to the exchange.

Other objects and structural details of the invention will be apparent from the following description when read in conjunction with the accompanying drawings forming part of this specification, wherein:

Fig. 1 is a diagrammatic top plan view of a contact plate according to the invention for use in a rectifying or contacting column,

Fig. 2 is a somewhat diagrammatic vertical sectional view of a contacting column provided with contact plates according to Fig. 1, said section being taken along line 22 of Fig. 1,

Fig. 3 is a diagrammatic top plan view of a different embodiment of a contact plate according to the invention,

Fig. 4 is a horizontal sectional view, on an enlarged scale, of a gas chimney and a gas deflecting cap of the contact plate shown in Figs. 1 and 2,

Fig. 5 is a horizontal sectional view, on an enlarged scale, of a gas deflecting cap of the contact plate shown in Fig. 3,

Fig. 6 is a somewhat diagrammatic top plan view of another embodiment of a contact plate according to the invention, the bafile plate being omitted in the right hand portion of said figure,

Fig. 7 is a top plan view of a distributing plate used in the contact plate shown in Fig. 6,

Fig. 8 is a top plan view of another embodiment of a distributing plate for use in the contact plate shown in Fig. 6,

Fig. 9 is a fragmentary vertical sectional view of a contact plate as shown in Fig. 6,

Fig. 10 is, on an enlarged scale, a fragmentary vertical sectional view similar to that shown in Fig. 9 illustrating a detail thereof,

Fig. 11 is a somewhat diagrammatic top plan view of a further embodiment of a contact plate according to the invention, one or more parts of the contact plate being omitted in various sectors of the figure so as to show underlying parts,

Fig. 12 is a vertical sectional view of a rectifying or contacting column showing two contact plates according to Fig. 11,

Fig. 13 is, on an enlarged scale, a fragmentary sectional view illustrating a portion of a contact plate according to Fig. 12,

Fig. 14 is a fragmentary sectional view of a strip-like member used for the construction of a base of a contact plate composed of a plurality of individual members,

Fig. 15 is a top plan view of the member shown in Fig. 14,

Fig. 16 is a top plan view of a triangular member used for the construction of a base of a contact plate composed of several members,

Fig. 17 is a diagrammatic top plan view of the base of a contact plate composed of a plurality of strip-like members,

Fig. 18 is a diagrammatic top plan view of the base of a contact plate composed of a plurality of triangular members,

Fig. 19 is, on an enlarged scale, a fragmentary top plan view of a portion of a distributing plate made of expanded metal, and

Fig. 20 is a sectional view taken on line 2020 of Fig. 19.

Referring now to Figs. 1 and 2, 30 generally indicates a contact plate for use in a contacting or rectifymg column 32, wherein a liquid and a gaseous medium, such as a gas or steam, are brought into intimate contact. The liquid is supplied to the upper portion of the column above the contact plate or plates 30 in a manner known per se for descending in the column and the gaseous medium is supplied to the column at a point below the contact plate or plates for ascending in the column.

The base 34 of the contact plate 30 is provided with a series of openings 36, each of which is surrounded by a gas inlet connecting branch or gas chimney b. According to the embodiment shown in the drawings, the gas chimneys b are integral with the base 34; if desired, however, the gas chimneys could be separate elements attached to the base in any suitable manner. The upper edges of the gas chimneys are on a level above the level of the base 34. As best shown in Fig. 1, two rows of gas chimneys b are arranged in two concentric circles around the vertical axis X of the contact plate 30.

Overflow pipes 1 arranged for leading the liquid from the circumference of a contact plate to the center of the next contact plate in sequence for delivering the liquid to the latter have their upper edges in a level above the level of the base 34, so that they cause a damming of a layer of liquid of predetermined height on said base in a static manner.

Each gas chimney b is covered by a bell-cap a, the lower, cylindrical portion of which rests on the base 34 of the contact plate. Each bell-cap is provided with a plurality of gas discharging passages or slots 0 at its lower portion. Said slots 0 extend from the lower edge of the bell-cap, so that a series of spaced teeth is formed.

As best shown in Figs. 1 and 4-, each bell-cap a is; arranged eccentrically to its associated gas chimney b in such a manner that its lower portion contacts same along a line. Preferably, the bell-cap a is rigidly connected with its associated gas chimney b, for example by welding along the line of contact. Thus, a certain number of the gas discharging slots 0 are partially or entirely covered by the wall of the associated gas chimney. Moreover, as best shown in Fig. 4, the gas conduit 38 formed by the space between the cylindrical walls of the eccentrically arranged gas chimney b and bell-cap a is of varying cross sections, so that dififerent amounts of gaseous .medium emitted from the gas chimney b and deflected by the bellcap a are lead to the various discharging passages or slots on the circumference of the bell-cap a. Therefore, owing to the partially narrowed cross-sections available for the passage of the gaseous medium, the gases or vapors passing through said slots c are distributed around the edge of the bell-cap a with a distinct effect of direction, as indicated by the arrows in Fig. 4. As a result, the main portion of the amount of gases discharged by the bell-cap flows in the direction of the arrow C.

During the operation of the column, the discharge passages c are submerged in a layer of liquid formed on the base 34 by the damming effect of the overflow pipe 1. The outlets of said passages c extend in a horizontal direction, so that the gaseous medium is introduced into the layer of liquid in a horizontal direction.

In Fig. l, the vectors C indicate the total energy of the main portion of the amount of gases or vapors discharged upon deflection by the eccentrically arranged bell-caps a into the layer of liquid. As will be readily understood, the overflow of the gaseous medium at each bell-cap a has its own field of forces determined by its position relative to the circumference and center of the contact plate and by the angle a (see Fig. 1) between the radius of the plate and the direction of movement imparted to the gaseous medium at the outlet of the bell-cap. Therefore, individual vectorial equations of the general form (wherein C denotes the total energy, CT denotes the tangential component of the kinetic energy and CR denotes the radial component of the kinetic energy) may be applied to each bell-cap outlet for the vector analysis or the kinetic energy of the gaseous medium emitted from the bell-cap outlet.

As shown in Fig. 1, the gas deflecting bell-caps a are arranged in such a manner relative to the associated gas chimneys b and to the vertical axis X of the contact plate 30, that each vector 'C at each bell-cap a is at the same angle at to the radius of the contact plate. Thus, the main portionof the amount of gases or vapors emitted from the gas deflecting bell-caps a is introduced into the layer of liquid in a uniform radial and tangential direction relative to the vertical axis X of the contact plate 3i) by the cooperation of the plurality of bell-caps arranged in the manner described above. Therefore the conditions for the creation of above mentioned stationary or stable motion of rotation of the layer of liquid in the direction of the arrow R and the advantages resulting therefrom can be readily fulfilled by a contact plate according to the invention.

The bell-caps a used in the embodiment shown in Fig. 1 may be of a design customary for bell-caps used in so-called bell contact plates or'bubble plates.

According to the embodiment shown in Figs. 3 and 5 two series of elongated tunnel-like gasdeflecting means a which with respect to shape may be of a design cfistomar'y in so-called tunnel .contact plates, are placed in two concentric circles on the base 134 of a contact plate 130. Each gas deflecting means a covers an associated gas chimney on the base 134. Again, the damrning of a layer of liquid on the base is statically conditioned by an overflow pipe 1, the upper edge of which is inalevel above the level of the base 134.

The'tunnel-like elements :1 are provided at their lower portion with a pluralityof parallel discharging passages or slots c preferably extending from their lower edge. Said passages c are arranged at that side of the element a which faces the center of the contact plate 130 when theelements 01. are placed thereon as'shown in Fig. 3. As may be readily gathered from Fig. 5, said parallel passages c cause a-discharge'of the gases-or vapors-into the liqwidin a uniform direction. Owing to 'the particular arrangement of the tunnel-like gas deflecting elements relative to the vertical axis of the contact plate, shown in Fig. 3, the vectors C at the outlet of each element a are at equal angles to radii of the contact plate, so that again-this time without an eccentric arrangement of the gas deflecting meansthe gases or vapors are discharged into the liquid in a uniform radial and tangential sense.

Above described embodiments shown in Figs. 1-5 make use of customary constructional elements as gas deflecting means (bell-caps, tunnels or the like), which, however, are arranged in a new manner and in new combinations for obtaining the desired effect; these elements (caps a or tunnels a,) being provided with discharge passages (slots 0 or 0 at their lower edges serve for defleeting the flow of gaseous medium emitted from the associated gas chimney and for discharging same in a substantially horizontal direction into the layer of liquid surrounding the discharge passages.

According to the embodiments of Figs. 6-13, h0wever, to be described later on, the gas deflecting means (bell caps a or elongated tunnel-like bodies) are used only for the purpose of deflecting the gases or vapors emitted from the associated gas chimneys and, consequently, are not equipped with teeth and slots at their lower edges. In these embodiments, the distribution of the gases and vapors and the introduction thereof into the liquid takes place-in analogy to the manner customary in connection with dynamically eifective contact plates working with a rotating layer of liquid-by the use of a layer of distributing means comprising a plurality of preformed distributing bodies provided with a series of discharging passages or by the use of a distributing plate extending over the entire area of the base of the contact plate and being provided with series of discharging passages. Said discharging passages, being arranged in parallel rows, extend from the lower surface of the distributing body or distributing plate to the upper surface thereof in a direction inclined to the plane of said distributing body or plate respectively. Said inclined discharging passages are arranged relative to each other in such a predetermined direction that the gases or vapors deflected by the gas deflecting means for passing through said passages are discharged therefrom into the layer of liquid above them in such a predetermined direction, that they cause a rotating motion of said layer of liquid around the vertical axis of the contact plate, the height of said layer of liquid, however-in contrast to purely dynamic contact platesbeing determined only by the position of the upper edges of the overflow passages.

Referring w, more in detail, to the embodiment of a contact plate illustrated by Figs. 6-10 which operates in the manner mentioned in the preceding paragraph, again a series of gas chimneys b are arranged on the base 334 of the contact plate 330. A series of overflow pipes 1 passes through the base 334 having their upper edges extending to a level above the level of the base 334 so as to cause the damming of a layer of liquid. A series of distributing elements 2 of profile form are arranged in the manner of a mosaic in the area between the gas chimneys b, on the base 334 of the contact plate. Said distributing bodies 2 may be made in any suitable manner. In a preferred embodiment shown in the drawings, said distributing bodies a are formed of rectangular blanks of sheet metal. The corners a (see Figs. 7 and 10) of such a blank are bent downwardly so as to form spacing legs holding the plate proper at a distance from the base 334 when placed thereon. Moreover, preferably, said blanks are made of expanded metal as illustrated by Figs. 19 and 20. The portions of the plate of expanded metal adjacent the discharging passages 0, thereof, arranged in parallel rows, are bent into directions inclined to the plane of the plate. According to Fig. 6 (upper right half) and Fig. 7, the distributing plates e are in the shape of a hexagon. As best shown in Figs. 6 and 10,

said hexagonal distributing plates e are arranged in such a manner around the gas chimneys b, that a passage 338 is formed which communicates with the space 340 between the plate 2 and the base 334.

The configuration of the distributing elements e depends on the chosen arrangement of the gas chimneys b,. In the lower right half of Fig. 6 and in Fig. 8 for example distributing elements e having the shape of an octagon are shown. However, the distributing elements may also have a configuration of a different geometrical form.

The individual distributing element e or 2' used in the contact plate of Figs. 6-10 may be made in a single operation from a blank; the assemblage of the bottom on the base 334 by means of such individual distributing elements is very simple.

A series of gas deflecting bell-caps a are placed on the bottom formed by the plurality of individual distributing plates 2 in such a manner, that each bell-cap covers a gas chimney b and that the interior of each bell-cap communicates with a passage 338 around the associated gas chimney.

The bell-caps (1,, rather flat in shape, are held in their positions by means of a baffle-plate 1, arranged above and engaged with said bell-caps. As best shown in the left half of Fig. 6, said baffle-plate f, is composed of a plurality of sector-plates. Each sector-plate is provided with inclined channels 342 arranged in parallel rows. Preferably the sector-plates of the baffle-plate f, are made of expanded metal of the type illustrated by Figs. 19 and 20. The channels 342 extend from the lower surface of the bafile-plate to the upper surface thereof in a direction inclined to the plane of the baffle-plate. The joints of the individual sector-plates of the baffle-plate J are covered by bars g connected by screw bolts h with the base 334 of the contact plate 330 whereby all parts of the contact plate are fixed.

As will be readily understood, gaseous medium emitted from a gas chimney b, is deflected by the associated bellcap as and passes through the passages 338 into the space 340 between the base 334 and the upper portion of the distributing element e. Then, the gaseous medium is discharged from said space 340 through the inclined discharging passages c (see Fig. 20) in the direction of the arrows shown in Figs. and into the layer of liquid above the distributing element e. The vector C shown in Figs. 7 and 8 and in the upper and lower right hand portions of Fig. 6 indicates the total kinetic energy inherent in the gaseous medium discharged from the inclined passages c of the distributing element. The vectorial diagrams of Fig. 6 show the tangential component CT and the radial component CR of the kinetic energy.

As best shown in the right hand portion of Fig. 6, the distributing elements a or a respectively are arranged in such a manner that the parallel rows of their discharging passages extend in different directions relative to the vertical axis of the central plate in different parts of the latter. The arrangement of the direction of the outlets of the discharging passages c3 relative to each other and relative to the vertical aXis of the contact plate is chosen in such a way that the outflow of the gaseous medium is uniformly distributed in a radial and tangential sense to the vertical axis of the contact plate.

A selected preference or accentuation of the radial or tangential direction of flow of the discharged gaseous medium may be obtained by choosing, for example, a hexagonal or octagonal shape of the distributing elements e or e. This feature is of great importance as it results from the so-called law of twisting forces that the effect of the centrifugal force on a particle is increased the nearer the particle is brought to the center of the contact plate, a feature, which, by the way, can also be observed clearly in connection with purely dynamic contact plates. Thus, it is possible to counter-act this condition by an appropriate higher accentuation of the 8 inwardly acting radial component of the kinetic energy.

As mentioned above, the baffle-plate f3 is provided with inclined channels 342 arranged in parallel rows. As may be gathered from the left hand portion of Fig. 6, said inclined channels 342 extend in different directions relative to the vertical axis of the contact plate in different sectors or zones of the baffle-plate. The outlets of said inclined channels are arranged so as to cause a flow of the discharged gaseous medium in uniform radial and tangential sense to the vertical axis of the contact plate. The vector-diagram C, Cr, CE for the discharged medium is shown in the left upper portion of Fig. 6. As will be readily understood, the discharge of the gaseous medium through the inclined channels of the bafile-platc f3 assures an intensive cyclone separation of the drops of liquid which may be carried along in the gaseous medium.

Referring now, more in detail, to the embodiment of a contact plate shown in Figs. 1ll3, a series of gas chimneys b4 are arranged on the base 434 of the contact plate 430. A distributing plate e4 provided with parallel rows of inclined discharge passages ('4 extending from its lower surface to its upper surface is placed on the upper ends of the gas chimneys, covering the latter. The distributing plate c4 extending over the entire area of the base 434 is composed of a plurality of sector-plates, preferably made of expanded metal of the type shown in Figs. 19 and 20. A series of overflow pipes 1 pass through the base 434 and the distributing plate e4. The upper edges of the overflow pipes 1 being at a level higher than the upper edges of the gas chimneys b4 and the upper surface of the distributing plate e4 carried by the former cause the damming of a layer of liquid. Each sector plate or zone of the distributing plate e4 has its inclined passages or arranged in a different direction. Said inclined passages 64 are arranged in a uniform tangential and radial sense to the vertical axis of the contact plate, in a manner as are used in purely dynamic contact plates. The vector diagram C, CR, CT for the gaseous medium emitted from the distributing plate 24 is shown in the upper right portion of Fig. 11. Bell-caps 114 or other gas deflecting means, for example tunnels or the like, are placed on the upper side of the distributing plate er in register with gas chimneys b4 on the other side of said distributing plate. The lower edges of said bell-caps a4 rest on the upper surface of said distributing plate e4; thus, in contrast to the previously described other embodiments of a contact plate, the lower portion of the bell-caps do not extend below the level of the upper edges of the gas chimneys. As best shown in Fig. 13, the gaseous medium emitted from a gas chimney b4, after being deflected by the bell-cap a4, passes, in downward direction, through an annular conduit 438 including inclined passages of the distributing plate e, into the space 440 between the distributing plate e4 and the base 434 of the contact plate; then, the gaeous medium being deflected again passes, in upward direction, through other inclined passages of the distributing plate er, and is discharged into the layer of liquid.

The gas deflecting bell-caps a4 are held in their position by a baffle-plate ii of the same construction as the baflie-plate f3 described above in connection with Figs. 6l0. The bafile-plate f4 connected to the base of the contact plate by screw bolts h is provided with inclined channels 442 arranged in parallel rows in its various zones in a predetermined relation to the vertical axis of the contact plate for causing an intensive cyclone separation of drops of liquid carried along in the gaseous medium. The vector-diagram C, Cr, CR for the gaseous medium emitted from the bafile-plate f4 is shown in the left hand portion of Fig. 11.

There is a distinct difference between the embodiment shown in Figs. 1113 and the other embodiments shown in Figs. 1-10. It will be noted that according to the embodiment of Figs. 11-13, in contrast to the embodiments of Figs. 1-10,, there is, in a purely static way, no blocking of the liquid with respect to the gases or vapors passing through the contact plate; on one hand, the upper edges of the gas chimneys b4 carrying the distributing plate at are below the level of the upper edges of the overflow pipes 1 and, on the other hand, the lower portions of the bell-caps a4 terminating in a plane above the upper edges of the gas chimneys b4 do not cover the side walls of the latter.

This embodiment of Figs. 11-13, results in a further, very important simplification of the construction of a contact plate, without, as proven by tests, incurring the risk of causing again a lower load limit. This embodiment is rendered possible by the fact that the liquid is pressed back by the gaseous medium, even by the smallest amounts thereof, in the narrowed cross-sections of the annular conduit 438 (see Fig. 13), so that the desired conditions are obtained for the operation of the contact-plate in the manner described above in connection with the other embodiments.

On the other hand, the narrowing of the cross-section in the annular conduit 438 has no disadvantageous influence on the resistance to flow of the contact plate; during the operation of the column only gases or vapors pass through the narrowed cross-section, being free from liquid for the reasons explained above, so that the resistance to flow of the contact plate is considerably reduced.

Owing to the strong rotation of the liquid obtained on contact plates according to the invention and owing to the thorough mixing caused by said rotation, it is possible to discharge the liquid simultaneously at different points from contact plates of large diameter, as illustrated by the arrangement of the overflow pipes l in Figs. 6, 11 and 12, without incurring the risk of creating paths of the liquid leading directly from the inlet to the outlet, thus impairing the exchange. This feature, especially, has the advantage that the spacing of the contact plates may be maintained even in columns of largest diameter, a feature which otherwise would be impossible in view of the necessary arrangement of return conduits for the liquid.

If the column is of a small diameter, however, it may be advisable to arrange the point of discharge of the liquid near the circumference of the contact plate and the point of delivery of the liquid to the next contact plate in sequence at the center of the latter, as shown in Figs. 1-3, inasmuch as this feature can be readily accomplished in columns having a small diameter.

The vector-diagrams C, Ca, C'r shown in Figs. 1, 3, 6 and 11 clearly illustrate that the action of the gas or vapor on the liquid takes place in any case in a uniform direction and with a radial component of the kinetic energy directed towards the center of the contact plate.

Owing to the fact that for the reasons set forth above, a contact plate according to the invention may operate with a layer of liquid of very small height, it is also possible to manufacture the contact plate in such a manner that, as shown in Figs. 14 and 15, the gas chimneys b' are produced by stamping sheet metal strips 34' or that as shown in Fig. 16, the gas chimneys b" are produced by stamping sheet metal plates of suitable shape, for example of triangular shape, and a single bell cap, not shown, may be placed over all the chimneys. Thus, the base of the contact plate may be composed of standardized elements, for example strips or triangular plates as exemplified by Figs. 17 and 18. In this way contact plates of any desired large diameter may be manufactured in a simple and economical way, as, in view of the high strength characteristics resulting from the deformation of the material, a great saving on material is obtained.

I have described preferred embodiments of my invention, but it is understood that this disclosure is for the purpose of illustration and that various omissions or changes in shape, proportion and arrangement of parts,

10 as well as the substitution of equivalent elements for those, herein shown and described, may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

For example, if desired, a baflle-plate of the type shown in the embodiments of Figs. 6-10 and 11-13 may also be arranged in the same manner in the embodiments shown in Figs. 1-2 and 3.

Furthermore, the expansion of the expanded material shown by way of example in Figs. 19 and 20 may be in lesser degree, so that the inclination of the passages is less and the gaseous medium is discharged in an almost horizontal direction.

What I claim is:

l. A contact plate, for use in a rectifying or contacting column wherein a liquid supplied through an inlet and discharged through a separate outlet is brought into intimate contact with a gaseous medium, said contact plate comprising in combination: a base having a circular circumference and having a series of gas chimneys forming passages for the gaseous medium, the upper open ends of said gas chimneys being in a level above the level of said base, a distributing plate spaced from said base and carried by the upper ends of said gas chimneys, said distributing plate covering the entire surface of the base and being divided into a plurality of zones, each zone having a series of discharging passages arranged in parallel rows and extending from the lower surface of the distributing plate to the upper surface thereof in a direction inclined to the plane of said distributing plate, overflow means passing through said base and said distributing plate for the discharge of liquid delivered to said base, the upper edge of said overflow means being in a level above the plane of said distributing plate so as to cause the damming of a layer of liquid of a predetermined height on said base, and a series of spaced cap-like gas deflecting means, each gas deflecting means being arranged on the upper surface of said distributing plate opposite a gas chimney engaged with the lower surface of the latter for deflecting the direction of flow of the gaseous medium emitted from the associated gas chimney so as to pass through discharging passages of the distributing plate downwardly into the space between said distributing plate and the base and, thence, through other discharging passages of the distributing plate upwardly into the layer of liquid covering said distributing plate, and the outlets of said rows of discharging passages being arranged around the vertical axis of said base in directions causing a discharge of the gaseous medium in a uniform radial and tangential direction to said vertical axis of the base whereby the layer of liquid is rotated about the center of said circular circumference of said base.

2. In a contact plate as claimed in claim 1, each zone of said distributing plate being in the shape of a sector.

3. In a contact plate as claimed in claim 1, said distributing plate being composed of a plurality of individual sector plates, each sector plate constituting one of said zones.

4. In a contact plate as claimed in claim 1, said distributing plate being composed of a plurality of individual sector plates made of expanded metal, each sector plate constituting one of said zones.

5. In a contact plate as claimed in claim 1, each of said cap-like deflecting means in conjunction with its associated gas chimneys forming passages of reduced cross-section for the gaseous medium whereby a discharge of the liquid through the gas chimneys ending below the level of the upper edge of the overflow means is prevented even if only a very small amount of gaseous medium is present.

6. In a contact plate as claimed in claim 1, a baffle plate arranged above said cap-like gas deflecting means and engaged with the latter for holding same in their position, and connecting means connecting said bafile-v plate with said base, said bafile plate being divided into a plurality of zones, each zone having a series of channels arranged in parallel rows and extending from the lower surface of the baffle plate to the upper surface thereof in a direction inclined to the plane of the baffle plate for leading the gaseous medium emitted from the upper surface of the layer of liquid into the space above said bafile plate, and the outlets of said rows of channels being uniformly directed to the vertical axis of said base in tangential and radial sense for causing an intensive vortex motion of the passing gaseous medium so as to cause separation of drops of liquid carried along.

7. A contact plate, for use in a rectifying or contacting column wherein a liquid supplied through an inlet and discharged through a separate outlet is brought into intimate contact with a gaseous medium, said contact plate comprising in combination: a base having a circular circumference and having a series of gas chimneys forming passages for the gaseous medium, the upper open ends of said gas chimneys being in a level above the level of said base, a distributing plate spaced from said base and carried by the upper ends of said gas chimneys, said distributing plate covering the entire surface of the base and being divided into a plurality of zones, each zone having a series of discharging passages arranged in parallel rows and extending from the lower surface of the distributing plate to the upper surface thereof in a direction inclined to the plane of said distributing plate, overflow means passing through said base and said distributing plate for the discharge of liquid delivered to said base, the upper edge of said overflow means being in a level T2 above the plane of said distributing plate so as to cause the damming of a layer of liquid of a predetermined height on said base, and a series of spaced cap-like gas deflecting means, each gas deflecting means being arranged on the upper surface of said distributing plate opposite a gas chimney engaged with the lower surface of the latter for deflecting the direction of flow of the gaseous medium emitted from the associated gas chimney so as to pass through discharging passages of the distributing plate downwardly into the space between said distributing plate and the base and, thence, through other discharging passages of the distributing plate upwardly into the layer of liquid covering said distributing plate.

References Cited in the file of this patent UNITED STATES PATENTS 1,427,430 Barbet Aug. 29, 1922 1,482,408 Piron Feb. 5, 1924 1,776,032 Kobernik Sept. 16, 1932 1,878,467 Clarke Sept. 20, 1932 2,091,349 Bergman Aug. 31, 1937 2,150,498 Geddes et a1. Mar. 14, 1939 2,376,940 Riemenschneider May 29, 1945 2,391,464 Larsen Dec. 25, 1945 2,560,077 Bloomer et al. July 10, 1951 2,568,749 Kittel Sept. 25, 1951 FOREIGN PATENTS 164,250 Austria Oct. 25, 1949 497,599 Belgium Sept. 15, 1950 613,550 France Aug. 27, 1926 

1. A CONTACT PLATE, FOR USE IN A RECTIFYING OR CONTACTING COLUMN WHEREIN A LIQUID SUPPLIED THROUGH AN INLET AND DISCHARGED THROUGH A SEPARATE OUTLET IS BROUGHT INTO INTIMATE CONTACT WITH A GASEOUS MEDIUM, SAID CONTACT PLATE COMPRISING IN COMBINATION: A BASE HAVING A CIRCULAR CIRCUMFERENCE AND HAVING A SERIES OF GAS CHIMNEYS FORMING PASSAGES FOR THE GASEOUS MEDIUM, THE UPPER OPEN ENDS OF SAID GAS CHIMNEYS BEING IN A LEVEL ABOVE THE LEVEL OF SAID BASE, A DISTRIBUTING PLATE SPACED FROM SAID BASE AND CARRIED BY THE UPPER ENDS OF SAID GAS CHIMNEYS, SAID DISTRIBUTING PLATE COVERING THE ENTIRE SURFACE OF THE BASE AND BEING DIVIDED INTO A PLURALITY OF ZONES, EACH ZONE HAVING A SERIES OF DISCHARGING PASSAGES ARRANGED IN PARALLEL ROWS AND EXTENDING FROM THE LOWER SURFACE OF THE DISTRIBUTING PLATE TO THE UPPER SURFACE THEREOF IN A DIRECTION INCLINED TO THE PLANE OF SAID DISTRIBUTING PLATE, OVERFLOW MEANS PASSING THROUGH SAID BASE AND SAID DISTRIBUTING PLATE FOR THE DISCHARGE OF LIQUID DELIVERED TO SAID BASE, THE UPPEREDGE OF SAID OVERFLOW MEANS BEING IN A LEVEL ABOVE THE PLANE OF SAID DISTRIBUTING PLATE SO AS TO CAUSE THE DAMMING OF A LAYER OF LIQUID OF A PREDETERMINED HEIGHT ON SAID BASE, AND A SERIES OF SPACED CAP-LIKE GAS DEFLECTING MEANS, EACH GAS DEFLECTING MEANS BEING ARRANGED ON THE UPPER SURFACE OF SAID DISTRIBUTING PLATE OPPOSITE A GAS CHIMNEY ENGAGED WITH THE LOWER SURFACE OF THE LATTER FOR DEFLECTING THE DIRECTION OF FLOW OF THE GASEOUS MEDIUM EMITTED FROM THE ASSOCIATED GAS CHIMNEY SO AS TO PASS THROUGH DISCHARGING PASSAGES OF THE DISTRIBUTING PLATE DOWNWARDLY INTO THE SPACE BETWEEN SAID DISTRIBUTING PLATE AND THE BASE AND, THENCE, THROUGH OTHER DISCHARGING PASSAGES OF THE DISTRIBUTING PLATE UPWARDLY INTO THE LAYER OF LIQUID COVERING SAID DISTRIBUTING PLATE, AND THE OUTLETS OF SAID ROWS OF DISCHARGING PASSAGES BEING ARRANGED AROUND THE VERTICAL AXIS OF SAID BASE IN DIRECTIONS CAUSING A DISCHARGE OF THE GASEOUS MEDIUM IN A UNIFORM RADIAL AND TANGENTIAL DIRECTION TO SAID VERTICAL AXIS OF THE BASE WHEREBY THE LAYER OF LIQUID IS ROTATED ABOUT THE CENTER OF SAID CIRCULAR CIRCUMFERENCE OF SAID BASE. 